Preheat the oven to 350 F. Take a 9x9 pan and spray, butter, or line with parchment to keep the brownies from sticking.
In a large mixing bowl, stir together the dry ingredients, then add the wet ingredients and combine until a thick batter forms.
Fold in the dark chocolate chunks/chips and pour the batter into your prepared pan. Spread to the edges and smooth out. Sprinkle with more dark chocolate chips or flavored ones.
Bake for 20-25 minutes...it really does vary, more recently it's been 24-25 minutes but my first several batches were done right around 20 so just keep an eye on them. You want them to not have a serious jiggle though a slight one is good, and if you lightly touch them they shouldn't be sticky at all. It's better for these to be slightly underdone vs. overdone---they'll be super dry if you overbake them.
Let the brownies cool down completely, for at least an hour, before serving.
You can store these on the counter in an airtight container for 1-2 days, or in the fridge for a few days. These do NOT do well in the freezer!